1. Field of the Invention
The present invention relates to a game system for displaying a polygon having three-dimensional coordinates to be projected on a two-dimensional plane.
2. Description of the Related Art
In such a game system, in general, a model or character that is an individual object to be displayed on a screen is composed of a number of polygons, each of which is a two-dimensional virtual figure of a triangle or rectangle. A Z-value indicating a depth is provided to each polygon, and a perspective (positional) relationship of polygons is determined based on this Z-value.
Conventionally, in such a game system, in the case where a plurality of polygons are drawn to be overlapped each other, a polygon with its smaller Z-value has been displayed with higher priority relevant to such an overlapped portion.
However, a new polygon is drawn to be overwritten at the boundary of a plurality of objects having a positional relationship with each other in a game picture, there occurs a case in which such positional relationship may be distorted from the viewpoint of a player. For example, in the case where it is specified to draw a polygon having its Z-value smaller than those of these polygons at the boundary of a forwardly positioned polygon and a backwardly positioned polygon, a polygon is displayed so as to be overlapped on both Of the forwardly and backwardly positioned polygons, so that a user hardly recognizes a depth in the picture.
The present invention has been made in order to solve the foregoing problem. It is an object of the present invention to provide a game system, capable of maintaining a three-dimensional image, even in the case where another polygon is drawn to be overwritten at the boundary of a plurality of polygons having a positional relationship displayed on a game picture.
In order to solve the foregoing problem, according to a first aspect of the present invention, there is provided a game system for drawing a plurality of polygons that configure a three-dimensional object disposed in a virtual three-dimensional space by projecting and converting the polygons on a projection plane in a visual coordinate system, and drawing these plurality of polygons so as to have a positional relationship in front and behind with each other based on a Z-value indicating a depth of a vertex coordinate of each polygon, said game system comprising; a mask polygon drawing device for drawing a mask polygon which inhibits another polygon and texture from being forwardly drawn afterward and maintains a backward drawing state; and a device for, in the case where a new polygon is to be drawn in front of said mask polygon, drawing said new polygon in a region other than a region superimposed on said mask polygon.
According to the thus configured game system, there is drawn a mask polygon which inhibits another polygon and texture from being forwardly drawn afterward and maintains a backward drawing state. In the case where a new polygon is to be drawn in front of the mask polygon, the new polygon is drawn in a region other than a region superimposed on the mask polygon. Therefore, the other polygon can be prohibited from being drawn on the mask polygon. Thus, the mask polygon is disposed at a desired position, thereby enabling a variety of performances on an image.
According to a second aspect of the present invention, there is provided a game system for drawing a plurality of polygons that configure a three-dimensional object disposed in a virtual three-dimensional space by projecting and converting the polygons on a projection plane in a visual coordinate system, and drawing these plurality of polygons so as to have a positional relationship in front and behind with each other based on a Z-value indicating a depth of a vertex coordinate of each polygon, said game system comprising: a device for drawing an opened polygon that contains a transparent region for maintaining a backward drawing state, a device for drawing a mask polygon in at least the transparent region of said drawn opened polygon, said mask polygon inhibiting another polygon and texture from being forwardly drawn afterward and maintaining a backward drawing state; and a device for, in the case where a new polygon is drawn to be superimposed in front of the opened polygon of which said mask polygon is drawn in said transparent region, drawing said new polygon in a region other than the transparent region of said opened polygon.
According to the thus configured game system, an opened polygon that contains a transparent region for maintaining a backward imaging state is drawn. Next, a mask polygon, which inhibits another polygon and texture from being forwardly drawn afterward and maintains a backward drawing state, is drawn in at least the transparent region of the drawn opened polygon. Then, in the case where a new polygon is drawn to be superimposed in front of the opened polygon of which the mask polygon is drawn in the transparent region, the new polygon is drawn in a region other than the transparent region of the opened polygon. Therefore, the other polygon is inhibited from being drawn relevant to the transparent region of the opened polygon, thus making it possible to maintain a three-dimensional image.
According to a third aspect of the present invention, there is provided a game system for drawing a plurality of polygons that configure a three-dimensional object disposed in a virtual three-dimensional space by projecting and converting the polygons on a projection plane in a visual coordinate system, and drawing these plurality of polygons so as to have a positional relationship with each other based on a Z-value indicating a depth of a vertex coordinate of each polygon, said game system comprising: a device for drawing an opened polygon that contains a transparent region for maintaining a backward drawing state; a device for drawing a mask polygon behind the drawn opened polygon so as to be superimposed by at least said transparent region thereof, said mask polygon inhibiting another polygon and texture from being forwardly drawn afterward and maintaining a backward drawing state; and a device for, in the case where a new polygon is drawn to be superimposed in front of the opened polygon, behind which the mask polygon is drawn, drawing said new polygon in a region other than the transparent region of the opened polygon. Accordingly, another polygon is inhibited from being drawn in the transparent area of the opened polygon, thus making it possible to maintain a three-dimensional image.
In the above described game system, the opened polygon and/or a new polygon can be provided with a texture. In such cases, various patterns can be displayed on the polygon.
According to a fourth aspect of the present invention, there is provided a drawing method in a game system for drawing a plurality of polygons that configure a three-dimensional object disposed in a virtual three-dimensional space by projecting and converting the polygons on a projection plane in a visual coordinate system, and drawing these plurality of polygons so as to have a positional relationship in front and behind with each other based on a Z-value indicating a depth of a vertex coordinate of each polygon, said drawing method comprising the processes of: drawing an opened polygon that contains a transparent region for maintaining a backward drawing state; drawing a mask polygon in at least the transparent region of said drawn opened polygon, said mask polygon inhibiting another polygon and texture from being forwardly drawn afterward and maintaining a backward drawing state; and drawing a new polygon to be superimposed in front of the opened polygon of which said mask polygon is drawn in said transparent region. Accordingly, another polygon is inhibited from being drawn in the transparent area of the opened polygon, thus making it possible to maintain a three-dimensional image.
According to a fifth aspect of the present invention, there is provided a drawing method in a game system for drawing a plurality of polygons that configure a three-dimensional object disposed in a virtual three-dimensional space by projecting and converting the polygons on a projection plane in a visual coordinate system, and drawing these plurality of polygons so as to have a positional relationship in front and behind with each other based on a Z-value indicating a depth of a vertex coordinate of each polygon, said drawing method comprising the process of: drawing an opened polygon that contains a transparent region for maintaining a backward drawing state; drawing a mask polygon behind the drawn opened polygon so as to be superimposed by at least said transparent region thereof, said mask polygon inhibiting another polygon and texture from being forwardly drawn afterward and maintaining a backward drawing state; and drawing a new polygon to be superimposed in front of the opened polygon of which said task polygon is drawn in said transparent region. Therefore, the other polygon can be inhibited from being drawn relevant to the transparent region of the opened polygon, thus making it possible to maintain a three-dimensional image.
According to a sixth aspect of the present invention, there is provided a computer readable storage medium having recorded therein a game program for drawing a plurality of polygons that configure a three-dimensional object disposed in a virtual three-dimensional space, the polygons being projected and converted on a projection plane in a visual coordinate system, and drawing the plurality of polygons so as to have a positional relationship in front and behind with each other based on a Z-value indicating a depth of a vertex coordinate of each polygon, said program causing said computer to function as; a mask polygon drawing device for drawing a mask polygon which inhibits another polygon and texture from being forwardly drawn afterward and maintains a backward drawing state; and a device for, in the case where a new polygon is to be drawn in front of said mask polygon, drawing said new polygon in a region other than a region superimposed on said mask polygon, respectively.
According to a seventh aspect of the present invention, there is provided a computer readable storage medium having recorded therein a game program for drawing a plurality of polygons that configure a three-dimensional object disposed in a virtual three-dimensional space, the polygons being projected and converted on a projection plane in a visual coordinate system, and drawing the plurality of polygons so as to have a positional relationship in front and behind with each other based on a Z-value indicating a depth of a vertex coordinate of each polygon, said program causing said computer to function as a device for drawing an opened polygon that contains a transparent region for maintaining a backward drawing state; a device for drawing a mask polygon in at least the transparent region of said drawn opened polygon, said mask polygon inhibiting another polygon and texture from being forwardly drawn afterward and maintaining a backward drawing state; and a device for, in the case where a new polygon is drawn to be superimposed in front of the opened polygon of which said mask polygon is drawn in said transparent region, drawing said new polygon in a region other than the transparent region of said opened polygon, respectively.
According to an eighth aspect of the present invention, there is provided a computer readable storage medium having recorded therein a game program for drawing a plurality of polygons that configure a three-dimensional object disposed in a virtual three-dimensional space, the polygons being projected and converted on a projection plane in a visual coordinate system, and imaging the plurality of polygons so as to have a positional relationship in front and behind with each other based on a Z-value indicating a depth of a vertex coordinate of each polygon, said program causing said computer to function as: a device for drawing an opened polygon that contains a transparent region for maintaining a backward drawing state; a device for drawing a mask polygon behind the drawn opened polygon so as to be superimposed by at least said transparent region thereof, said mask polygon inhibiting another polygon and texture from being forwardly drawn afterward and maintaining a backward drawing state; and a device for, in the case where a new polygon is drawn to be superimposed in front of the opened polygon, behind which the mask polygon is drawn, drawing said new polygon in a region other than the transparent region of the opened polygon.
Therefore, the program of the storage medium according to the seventh to ninth aspects of the invention is executed by a game system computer, whereby the game system of the present invention can be configured.